Figure

Shapes and geometry

Cylinders

Calculate closed-cylinder volume and surface area from diameter and height.1

For a circular cylinder, volume depends on the base-circle area and perpendicular height. Figure’s closed-cylinder surface area includes the curved side and both ends. Radius and diameter describe different inputs for the same base circle.

For radius r and perpendicular height h, cylinder volume = π × r² × h. Closed-cylinder surface area = 2π × r × h + 2π × r²: the curved side plus two circular ends. Convert diameter to radius before using these formulas.

The example’s diameter is 2 ft 4 in, so its radius is 1⅙ ft. At 4 ft 6 in high, the volume is π × (7/6)² × 4.5 ≈ 19.24226 ft³. An open-ended shell uses a different surface-area total from the closed cylinder shown here.

Closed cylinder

Use diameter and height. Read cylinder volume, then the other shape results.

Start a new calculation

Use 2nd if a unit is above its button.

  1. Start fresh

    Press Clear entry, then Clear entry.

  2. Press the keys

    Press Select length units.

Open Cylinder

Skip if this mode is already open. Skip Close if no mode is open.

  1. Press Close calculation mode, then Open Cylinder.

Enter and calculate

  1. Diameter

    Press 2, then feet, then 4, then inches, then Store diameter.

  2. Height

    Press 4, then feet, then 6, then inches, then Store height.

  3. Complete the value

    Press Equals.

Results in orderPress = to continue

  1. Cylinder volume19.24226 cubic feet
  2. Closed-cylinder surface area41.53884 square feet
  3. Cylinder volume again19.24226 cubic feet

Keep in mind

Surface area includes both ends. Use Radius instead of Diameter when you know half the width.

Display assumptions

  1. Area units: Automatic; Volume units: Automatic. ↩

Keep the guide beside your calculation.

These examples are built into Figure. Open Help while you calculate, then return to the same guide and reading position.

See Help in Figure →